The invention relates to an apparatus for closing packages made from a heat-sealable material of the kind that is disclosed in U.S. Pat. No. 4,768,326. In the known apparatus, the recesses for the flexible sealing faces are disposed such that the flexibility of the sealing faces is the same over the entire height of the transverse seam of the package, and is greatest along the transverse seam in the region of the longitudinal seam of the package. To that end, an additional longitudinal slit is made in the sealing face, in the region of the longitudinal seam of the package. It is disadvantageous that in the region of the additional longitudinal slit, the sealing quality is critical because the sealing pressure there is slight.
From German Patent Disclosure DE 29 34 807 A1, it is also known, to compensate for different numbers of layers of packaging material, along a sealing seam of a bag package at the sealing jaw in the region of the sealing seam, to dispose a deformable heat transfer means, filled with a medium, which is surrounded by a covering. Such an apparatus is relatively complicated in structure because of the various components. From German Utility Model DE-GM 94 13 035, an apparatus is also known, in whose sealing jaws elongated silicone inlays are provided, to enable compensating for a different number of layers of packaging material along a sealing seam of a bag package. However, the use of silicone has the disadvantage that the thermal conductivity of silicone from the remaining region of the sealing jaws is highly variable, which results in problems in operation with regard to the sealing quality.
The apparatus according to the invention for closing packages made from a heat-sealable material, has the advantage over the prior art that with a simple structure, because additional add-on parts are dispensed with, especially well-sealed transverse seams are made possible, since different sealing pressures are attained both transversely and longitudinally of the transverse seam, in such a way that the sealing pressure adapts itself especially well to the different thicknesses of material.
Further advantageous refinements of the apparatus according to the invention for closing packages from a heat-sealable material will become apparent from the disclosure.